The past twenty years have witnessed an incredible variety of printers designed for digital computers. For years, the line printer was the mainstay of the computer industry. Then, in the mid-1970's, the personal computer revolution began with the appearance of primitive computers based on the S-100 bus. With the appearance of more user-friendly computers from Apple Computer and, later, from IBM Corporation, the demand for personal computers soared. The public's almost insatiable appetite for personal computers has spawned a virtual explosion of technology. Printer technology has been one of the principal beneficiaries of that technology explosion. Early on, dot-matrix printers grabbed the lion's share of the market. For less than a decade, daisywheel printers shared the limelight for letter-quality printing tasks. Thermal printers were briefly used for portable applications. High-resolution dot-matrix printers and ink-jet printers sounded the death knell for daisywheel printers. Though greatly reduced in number, dot matrix printers seem to have found a niche for multiple form printing applications.
Laser computer printers have been around almost since the beginning of the personal computer revolution. In late 1980, Xerox Corporation introduced a laser printer for mainframe computers. Retail priced at a lofty $298,000, it could print more than 30 pages a minute. However, it was not until the Hewlett Packard Company began marketing the LaserJet series of laser printers that laser printers for personal computers became commonplace. Color laser printers, which are now becoming more affordable, may eventually become as ubiquitous as the black-and-white laser printers.
Modern electronic printers (especially those employing laser copying technology) are generally equipped with at least one replaceable component, such as a toner cartridge. Frequently, there is a need to install a peripheral device on the replaceable component. Such peripheral device may include, without limitation, a microprocessor, a non-volatile memory, a toner quantity sensor, an environmental condition sensor, a photoconductor condition sensor, or a print quality sensor. Each such device would generally require some sort of power source and would need to communicate with the printer engine. Current approaches to providing connectivity between a host printer engine and a peripheral device on the replaceable component involve making direct electrical contact between the printer engine and the peripheral. In order to handle both communications and power transfer, at least four electrical contacts may be required. Typically, such contacts are rather delicate, as they must be manufactured with a high degree of mechanical precision in order to maintain a required level of compactness. Such contacts typically involve a sliding action during the connection and disconnection process. Although the sliding action tends to wipe away dirt and other contaminants at the contact site, thus improving the electrical connection, it also creates wear on plated materials. As the plating is worn away, exposing a base metal more prone to corrosion, contact reliability will degrade. Corrosion-related contact degradation may be exacerbated by the presence of ozone within the printer body. Ozone, a strong oxidizing compound, is generated during certain electrophotographic processes. If spring-type electrical contacts are employed to make the required connections, they may be subject to bending or other damage which would impair the reliability of the connection.
Consequences related to the foregoing problems can be anything from merely an annoyance to printer inoperability.
What is needed is a contactless connection system for providing power and communications coupling to a peripheral device on a replaceable printer component.